Not Applicable.
Climatic influences, such as heat and cold, cause steel, concrete and other elements of bridges, whether highway, railway, or recreational, for example, to expand and contract in varying increments over time. By such movement, the integrity of the bridge can be eroded and ultimately destroyed. In particular, the more extreme freeze/thaw cycles reduce the strength of the bridge, and the bridge must therefore be constructed with more strength than would otherwise be necessary. In response to these problems, the federal government is currently funding research for extending the longevity of bridges.
In addition, during inclement cold weather, bridges and underpasses tend to ice over more quickly than the roadways leading to and from the bridges and underpasses. It is well recognized in the art that intermittent freezing and thawing greatly increase the hazards of winter driving. Most of the accidents result from the fact that the paving on the bridges and underpasses become coated with frost, ice or snow sooner and more often than the approaching pavements which result in the unwary driver frequently skidding upon entering the bridge or underpass.
It would represent an advance in the state of the art to provide a structure, such as a bridge or a culvert, which did not suffer from the aforementioned problems of the movement of the bridges, and the bridges and underpasses becoming coated with frost, ice or snow sooner and more often than their approach pavements. It is to such a unique structure having an insulated support assembly that the present invention is directed.
Broadly, the present invention relates to a structure, which in one preferred embodiment can be utilized as a bridge for supporting a road along a road axis over an underpass space spanned by the bridge or in a second preferred embodiment can form a culvert. In the one preferred embodiment, the road has a predetermined width extending in a direction transverse to the road axis. The structure includes two footings underlying the road with each footing being securely mounted to the earth. The footings are spaced apart in a direction substantially parallel to the road axis.
The structure also includes an arcuate support assembly supported by the footings. The support assembly extends at least the width of the road and traverses the underpass space for supporting the road across the underpass space spanned by the structure. The support assembly includes a substantially continuous inner shell, a plurality of rigid, resilient beams, an insulating material, and an outer shell.
The substantially continuous inner shell has a width at least corresponding to the road. The inner shell extends between the two footings so as to define the underpass space spanned by the structure.
The rigid, resilient beams surmount the inner shell. Each beam has a first end supported by one of the footings, and a second end supported by the other footing. The beams are spatially disposed in a direction transverse to the road axis and have a longitudinal axis extending in a direction substantially parallel to the road axis.
The insulating material is positioned between each of the beams for thermally isolating the road and the remainder of the support assembly from the underpass space and substantially preventing the transfer of heat there through.
The outer shell has a first end supported by one of the footings, and a second end supported by the other footing. The outer shell substantially encases the beams and the insulating material.
The substantially fluid impermeable material substantially encases the support assembly and a fill material extends from the substantially fluid impermeable material to support the road.
The support assembly also includes a pair of sidewalls extending parallel to the road axis on either side of the support assembly. The sidewalls are provided with an inner insulating layer to prevent heat from migrating through the sidewalls.
Thus, it can be seen that the insulating material provided between the beams and in the sidewall substantially prevent the fill material, and thus the road supported thereby, from losing heat through the sidewalls and the support assembly. Furthermore, the fill material acts as an insulator to insulate the support assembly. This stabilizes the temperature of the structure so as to prevent or reduce the aforementioned problems associated with the expansion and contraction of the structure, and the icing over of the road supported thereby.
In the colder geographic regions where there are extended periods of below freezing weather, a heat exchange assembly can be disposed throughout the fill material, the roadbed or the road extending through the underpass to selectively maintain the temperature of the fill material, the roadbed or the road extending through the underpass within a predetermined range so as to reduce the possibility of the road supported by the structure or passing through the underpass from icing over. A temperature control source is connected to the heat exchange assembly for providing a source of heat to the heat exchange assembly for controlling the temperature of the fill material, the roadbed, or the road passing through the underpass. The temperature control source is controlled by an environmental control computer which receives information from 1) various temperature sensors disposed in the roadbed, the fill material, or the road passing through the underpass, 2) a wind sensor located near the structure, or 3) a weather information receiver receiving information from any suitable source of weather forecasts, such as the National Weather Service. The environmental control computer receives the various information discussed above, and selectively controls the temperature control source to control the temperature of the road passing over the structure, the fill material and thus, the temperature of the support assembly, and the road passing through the underpass defined by the structure so that the expansion and contraction of the support assembly, and the icing over of the road passing over the structure, and the road passing through the underpass space are substantially reduced.
Thus, it can be seen that the applicants"" unique structure represents an advance in the state-of-the-art relating to structures and bridge support assemblies.